Now apart from its history, as a film I still like TLW as it has distinct acts, tells a large scale story and is layered with multiple character subplots and messages that have a direct connection with the first. I actually liked several of the characters, and some had very strong, established personalities that were memorable. It's Spielberg's worst and messiest film, but it's still a Spielberg film; it's not like he forgot how to direct. It was cinematically superb as usual in a technical sense. I enjoyed it a lot for its spectacle at the time, but I can still enjoy it now.
Good analysis. I agree with a lot of what you had to say (apart from the facts, which are facts so I can't disagree there) but I think you said it best when you said that the film was largely cynical due to the pressure that Spielberg was facing. Like Temple of Doom being excessively dark because George Lucas was pissed off and down in the dumps when he wrote it, The Lost World definitely seems to share some of those sensibilities. I don't hate it or disregard it. I fully count it as a legitimate follow-up, but it's not what I personally really desire from Jurassic Park both story-wise and tonally, and this brings me back to the core of why I enjoyed the third one more.
The Lost World, I felt, had "sequel" stamped all over it-- and I mean both the book and film. A secondary character in the original was brought back as the protagonist, and that's one of my main points of frustration. I don't see Jurassic Park as being a character-centered story. As much as I like some of the characters, I don't think it's particularly meant to be character-driven. It's not a character study, but rather a commentary of several themes. The characters can help drive the point home, sure, but when I think about Jurassic Park my mind doesn't go to Grant or Malcolm right off the bat.
And yes, this is a criticism I share with Jurassic Park III. I felt it was incredibly dishonest and against character for Grant to go back for any reason. They tried to establish that he needed research funds through the whole fund-raising campaign, but I don't think that he would have went for the money despite it only being a fly-over, and it irks me to no end when they just flash a blank check at him and it cuts to the plane. That never sat well with me. Jurassic III's main plot of the kid getting stranded on the island didn't need Grant, but at least they used him to help extrapolate the raptor intelligence sub-plot.
I think what might have worked better for me is just having Billy be the main character that goes to the island, while Grant is only really at the beginning and is just some cynical old man but Billy hasn't seen the dinosaurs and he has that spark of energy and excitement that Grant had before
he saw the dinosaurs, and the story could have still worked out well with Billy going with the Kirby's, taking the eggs, putting them in danger but then helping return the eggs at the end. I don't think his character, as written, would have made for a tremendously interesting protagonist, but I didn't think Grant was a super interesting protagonist either. He was good and I like Neill a lot, but again none of these characters are particularly deep or fascinating.
My apologies for rambling so much about it, and I know that this post is kind of all over the place, but I'm just trying to explain why The Lost World was a bit too dark and joyless to me whereas the third one, while I had plenty of issues with it and still some of the same issues I had with the second, was still more entertaining and engaging to me. I wish the script had been better and more fleshed out as there were bites of interesting details in there that never really came to fruition, but I still found the raptor sub-plot to be a lot more interesting and maybe even important to the story than anything in the second one.